Development of a source-drain electrode coated with an insulation layer for detecting concentration changes in a nitrate ion solution

T. Isoda, H. Makimoto, H. Imanaga, R. Imamura, J. Pawlat, T. Ueda

    Research output: Contribution to journalArticle

    7 Citations (Scopus)

    Abstract

    A chip-mounted source-drain electrode coated with an insulator layer was investigated with respect to its ability for monitoring in a concentrated nitrate ion solution. Exposing the electrode surface to highly concentrated nitrate ion solutions resulted in an increase in the detection voltage, while weakly concentrated solutions caused the detection voltage to decrease. Semi-circular shaped microelectrodes consisted of an Au/Cr film of 1/0.1 μm thickness on a glass chip, constructed using photolithography. A novolac resin or fluoro-olefin vinyl ether copolymer was used as the precursor of an insulator layer on the source-drain electrode. NaNO3 solutions of 1.0 × 10-6 to 1.0 mol l-1 (1 μl) were applied to the insulated electrode, and the chemical sensitivity was evaluated by measuring the detection voltage. The effects of thickness, insulator type, solution, and sensor material, on the chemical sensitivity were investigated. For a novolac resin insulator layer of thickness <2.5 μm, the sensor voltage was noticeably unstable, whereas a thicker insulator layer (>5 μm) resulted in a sensor voltage that showed a linear response depending on the NaNO3 concentration in the range of 1.0 × 10-6 to 1.0 × 10-3 mol l-1. The responsiveness of the sensor was improved with increasing insulator layer thickness. Optimization of the insulator thickness is therefore necessary if an effective sensor is to be realized. Sensor detection was also effected by the kind of solution and electrode material. The placing of a liquid droplet on the insulator surface resulted in the formation of an electric double layer at the boundary surface. Here, the molecules within the insulator become polarized, and a charge is formed at the boundary surface between the liquid and solid, and on the reverse side of the insulator. In this case, the relationship between the source-drain electrode current and the sensor voltage follows Ohm's law. Based on this principle, a source-drain electrode produces a signal in response to changes in current originating from polarization of the insulator layer.

    Original languageEnglish
    Pages (from-to)805-815
    Number of pages11
    JournalSensors and Actuators, B: Chemical
    Volume123
    Issue number2
    DOIs
    Publication statusPublished - 2007 May 21

    Fingerprint

    insulation
    Nitrates
    nitrates
    Insulation
    insulators
    Ions
    Electrodes
    electrodes
    Sensors
    ions
    Electric potential
    sensors
    electric potential
    Resins
    resins
    Microelectrodes
    Liquids
    Alkenes
    Photolithography
    chips

    Keywords

    • Chemical sensor
    • Electrode
    • Insulator
    • MEMS
    • Nitrate ion

    ASJC Scopus subject areas

    • Analytical Chemistry
    • Electrochemistry
    • Electrical and Electronic Engineering

    Cite this

    Development of a source-drain electrode coated with an insulation layer for detecting concentration changes in a nitrate ion solution. / Isoda, T.; Makimoto, H.; Imanaga, H.; Imamura, R.; Pawlat, J.; Ueda, T.

    In: Sensors and Actuators, B: Chemical, Vol. 123, No. 2, 21.05.2007, p. 805-815.

    Research output: Contribution to journalArticle

    Isoda, T. ; Makimoto, H. ; Imanaga, H. ; Imamura, R. ; Pawlat, J. ; Ueda, T. / Development of a source-drain electrode coated with an insulation layer for detecting concentration changes in a nitrate ion solution. In: Sensors and Actuators, B: Chemical. 2007 ; Vol. 123, No. 2. pp. 805-815.
    @article{38dd591787c143f29d4bf780f93f6764,
    title = "Development of a source-drain electrode coated with an insulation layer for detecting concentration changes in a nitrate ion solution",
    abstract = "A chip-mounted source-drain electrode coated with an insulator layer was investigated with respect to its ability for monitoring in a concentrated nitrate ion solution. Exposing the electrode surface to highly concentrated nitrate ion solutions resulted in an increase in the detection voltage, while weakly concentrated solutions caused the detection voltage to decrease. Semi-circular shaped microelectrodes consisted of an Au/Cr film of 1/0.1 μm thickness on a glass chip, constructed using photolithography. A novolac resin or fluoro-olefin vinyl ether copolymer was used as the precursor of an insulator layer on the source-drain electrode. NaNO3 solutions of 1.0 × 10-6 to 1.0 mol l-1 (1 μl) were applied to the insulated electrode, and the chemical sensitivity was evaluated by measuring the detection voltage. The effects of thickness, insulator type, solution, and sensor material, on the chemical sensitivity were investigated. For a novolac resin insulator layer of thickness <2.5 μm, the sensor voltage was noticeably unstable, whereas a thicker insulator layer (>5 μm) resulted in a sensor voltage that showed a linear response depending on the NaNO3 concentration in the range of 1.0 × 10-6 to 1.0 × 10-3 mol l-1. The responsiveness of the sensor was improved with increasing insulator layer thickness. Optimization of the insulator thickness is therefore necessary if an effective sensor is to be realized. Sensor detection was also effected by the kind of solution and electrode material. The placing of a liquid droplet on the insulator surface resulted in the formation of an electric double layer at the boundary surface. Here, the molecules within the insulator become polarized, and a charge is formed at the boundary surface between the liquid and solid, and on the reverse side of the insulator. In this case, the relationship between the source-drain electrode current and the sensor voltage follows Ohm's law. Based on this principle, a source-drain electrode produces a signal in response to changes in current originating from polarization of the insulator layer.",
    keywords = "Chemical sensor, Electrode, Insulator, MEMS, Nitrate ion",
    author = "T. Isoda and H. Makimoto and H. Imanaga and R. Imamura and J. Pawlat and T. Ueda",
    year = "2007",
    month = "5",
    day = "21",
    doi = "10.1016/j.snb.2006.10.029",
    language = "English",
    volume = "123",
    pages = "805--815",
    journal = "Sensors and Actuators, B: Chemical",
    issn = "0925-4005",
    publisher = "Elsevier",
    number = "2",

    }

    TY - JOUR

    T1 - Development of a source-drain electrode coated with an insulation layer for detecting concentration changes in a nitrate ion solution

    AU - Isoda, T.

    AU - Makimoto, H.

    AU - Imanaga, H.

    AU - Imamura, R.

    AU - Pawlat, J.

    AU - Ueda, T.

    PY - 2007/5/21

    Y1 - 2007/5/21

    N2 - A chip-mounted source-drain electrode coated with an insulator layer was investigated with respect to its ability for monitoring in a concentrated nitrate ion solution. Exposing the electrode surface to highly concentrated nitrate ion solutions resulted in an increase in the detection voltage, while weakly concentrated solutions caused the detection voltage to decrease. Semi-circular shaped microelectrodes consisted of an Au/Cr film of 1/0.1 μm thickness on a glass chip, constructed using photolithography. A novolac resin or fluoro-olefin vinyl ether copolymer was used as the precursor of an insulator layer on the source-drain electrode. NaNO3 solutions of 1.0 × 10-6 to 1.0 mol l-1 (1 μl) were applied to the insulated electrode, and the chemical sensitivity was evaluated by measuring the detection voltage. The effects of thickness, insulator type, solution, and sensor material, on the chemical sensitivity were investigated. For a novolac resin insulator layer of thickness <2.5 μm, the sensor voltage was noticeably unstable, whereas a thicker insulator layer (>5 μm) resulted in a sensor voltage that showed a linear response depending on the NaNO3 concentration in the range of 1.0 × 10-6 to 1.0 × 10-3 mol l-1. The responsiveness of the sensor was improved with increasing insulator layer thickness. Optimization of the insulator thickness is therefore necessary if an effective sensor is to be realized. Sensor detection was also effected by the kind of solution and electrode material. The placing of a liquid droplet on the insulator surface resulted in the formation of an electric double layer at the boundary surface. Here, the molecules within the insulator become polarized, and a charge is formed at the boundary surface between the liquid and solid, and on the reverse side of the insulator. In this case, the relationship between the source-drain electrode current and the sensor voltage follows Ohm's law. Based on this principle, a source-drain electrode produces a signal in response to changes in current originating from polarization of the insulator layer.

    AB - A chip-mounted source-drain electrode coated with an insulator layer was investigated with respect to its ability for monitoring in a concentrated nitrate ion solution. Exposing the electrode surface to highly concentrated nitrate ion solutions resulted in an increase in the detection voltage, while weakly concentrated solutions caused the detection voltage to decrease. Semi-circular shaped microelectrodes consisted of an Au/Cr film of 1/0.1 μm thickness on a glass chip, constructed using photolithography. A novolac resin or fluoro-olefin vinyl ether copolymer was used as the precursor of an insulator layer on the source-drain electrode. NaNO3 solutions of 1.0 × 10-6 to 1.0 mol l-1 (1 μl) were applied to the insulated electrode, and the chemical sensitivity was evaluated by measuring the detection voltage. The effects of thickness, insulator type, solution, and sensor material, on the chemical sensitivity were investigated. For a novolac resin insulator layer of thickness <2.5 μm, the sensor voltage was noticeably unstable, whereas a thicker insulator layer (>5 μm) resulted in a sensor voltage that showed a linear response depending on the NaNO3 concentration in the range of 1.0 × 10-6 to 1.0 × 10-3 mol l-1. The responsiveness of the sensor was improved with increasing insulator layer thickness. Optimization of the insulator thickness is therefore necessary if an effective sensor is to be realized. Sensor detection was also effected by the kind of solution and electrode material. The placing of a liquid droplet on the insulator surface resulted in the formation of an electric double layer at the boundary surface. Here, the molecules within the insulator become polarized, and a charge is formed at the boundary surface between the liquid and solid, and on the reverse side of the insulator. In this case, the relationship between the source-drain electrode current and the sensor voltage follows Ohm's law. Based on this principle, a source-drain electrode produces a signal in response to changes in current originating from polarization of the insulator layer.

    KW - Chemical sensor

    KW - Electrode

    KW - Insulator

    KW - MEMS

    KW - Nitrate ion

    UR - http://www.scopus.com/inward/record.url?scp=34247615961&partnerID=8YFLogxK

    UR - http://www.scopus.com/inward/citedby.url?scp=34247615961&partnerID=8YFLogxK

    U2 - 10.1016/j.snb.2006.10.029

    DO - 10.1016/j.snb.2006.10.029

    M3 - Article

    AN - SCOPUS:34247615961

    VL - 123

    SP - 805

    EP - 815

    JO - Sensors and Actuators, B: Chemical

    JF - Sensors and Actuators, B: Chemical

    SN - 0925-4005

    IS - 2

    ER -